This invention relates generally to the cutting of a continuously moving web, and more particularly, to means for selectively directing segments of a slit moving web of double face corrugated paperboard between a slitter-scorer machine and a cut-off machine.
A corrugated paperboard web has traditionally been slit by a rotatable turret-machine known generally as a "triplex". A triplex includes three sets of shafts provided with rotary slitter knives and scoring heads. The shafts are mounted on a rotatable turret so that one pair of shafts, generally the pair temporarily disposed at the top, is actively cutting the web while the lower pairs are inoperative whereby an operator may reset the heads on the lower pairs of shafts. Since the paperboard web was always fed at the same elevation, web directors for guiding the web to and from the triplex were relatively simple. For example, see U.S. Pat. Nos. 3,307,441 and 3,489,043.
At the end of a production run, it was necessary to slit the web transversely and slow down the speed of the web to thereby provide a gap in the web to facilitate indexing the triplex for the next production run. Reducing the speed of the web not only impedes production but is deleterious to the quality of the corrugated paperboard. To overcome these problems, the slitter-scorer was changed so that the web was alternately fed at different elevations. For example, see U.S. Pat. Nos. 3,831,502; 3,882,765; and 4,041,819.
Each of the web directors described in the aforementioned patents for feeding webs selectively from different elevations is complex and expensive. Furthermore, the large number of movable members renders the apparatus dangerous to operators, particularly if a jam occurs whereby it is necessary for the operator to reach into the machine.
In view of the demand by the industry for slitter-scorers requiring negligible time for changing from one production order to another production order, bi-level slitter-scorers have gained wide acceptance. Accordingly, there is now a great need for a simple, safe, and inexpensive web director which can feed a web from any one of two elevations of a slitter-scorer to any one of two elevations at a cut-off machine.